How long it takes to die from carbon monoxide poisoning depends on the severity of the poisoning, the treatment measures taken after the poisoning, etc., and requires specific analysis of each case. In milder cases of carbon monoxide poisoning, symptoms such as dizziness, headache, nausea and vomiting will occur. If the person is removed from the poisoned environment in time and breathes fresh air, he will recover quickly and usually will not cause death. However, if it is found late, or if a large amount of carbon monoxide is inhaled, it may often enter the stage of severe poisoning, and the patient may be unconscious and may die within a few hours if he or she does not receive fast and effective treatment, and there are also patients who survive, but are left with serious sequelae, such as delayed encephalopathy and limb atrophy, etc. The prognosis is poor. The most important and effective treatment for carbon monoxide poisoning is hyperbaric oxygen therapy, which can reduce the risk of developing delayed encephalopathy to some extent. Patients with moderate to severe poisoning need to be aware that hyperbaric oxygen therapy should not be abandoned just because they are sober.